In this age of information, there is a need for communication systems that provide the connectivity and capacity to meet increasing user demands. Data-intensive applications such as remote computing, Internet browsing, multimedia communication, and others place significant strain on the existing communication infrastructure. The public switched telephone network (PSTN), long-haul data networks, and other developed wireline and wireless networks cannot meet these demands.
One approach to increasing connectivity and capacity is to upgrade the existing terrestrial infrastructure. New terrestrial systems include wireless data service at the personal communications services (PCS) frequency band, data transport over coaxial cable installed for cable television, or an assortment of digital subscriber line services over twisted wire pairs installed for telephone networks. These terrestrial solutions require significant time to prepare for and install the infrastructure before service can be provided, and also require costly maintenance of the equipment due to vandalism, lightning, provision changes, frequency reassignments, and the retuning of radiofrequency (RF) equipment. Also, terrestrial solutions suffer from Rayleigh fading caused by interference scattering from terrain and buildings, which demands high dynamic range and sophisticated equipment to compensate for extreme variations in received signal strength.
Another approach to increasing connectivity and capacity is to upgrade the satellite-based infrastructure operating in geo-synchronous orbit (GEO) and low-earth orbit (LEO). Like terrestrial systems, satellite systems often take years to deploy fully, especially large constellation LEO systems. Also, satellite systems are costly to maintain or upgrade. Consequently, satellite systems include proven communication technology designed to operate reliably in a harsh radiation environment, which significantly increases the system cost and reduces system capacity. Satellite systems also suffer from limited weight and power capacities, and fail to provide the desired circuit density to service densely populated areas.